An image pickup element using an organic material (organic photodiode) can photoelectrically convert only a specific color (wavelength band). Then, because of having such a feature, when the organic photodiode is used as an image pickup element in a solid-state image pickup device, a sub-pixel is constituted by a combination of an on-chip color filter (OCCF) and an image pickup element. It is possible to obtain a structure (laminated image pickup element) in which the sub-pixels are laminated on one another. Such a structure is impossible in a past solid-state image pickup device in which the sub-pixels are two-dimensionally arranged. Therefore, since incident light can be received at a high efficiency, the promotion of high sensitivity of the solid-state image pickup device is expected. In addition, since mosaic processing is not required, there is an advantage that a false color does not occur.
The organic photodiode used in the solid-state image pickup device and the image pickup element has the same or similar structure as or to that of various organic thin film solar cells. Heretofore, a structure utilizing p-n junction or p-i-n junction (for example, JP 2006-033942A), a structure utilizing a bulk-hetero structure (for example, JP 2007-123707A), and a structure utilizing a buffer layer (for example, JP 2007-311647A and JP 2007-088033A) has been well known as the structure of the organic photodiode, and have exclusively aimed at enhancing the photoelectric conversion efficiency.